The amusement park was closed an hour ahead of schedule because of a large fight that broke out there. Police received a report of the brawl shortly before 7:00 PM. The incident, apparently sparked by queue jumping at a park ride, reportedly involved up to 150 young people.
An earlier incident at about 2:30 in the afternoon involved considerably younger children, aged 7 to 14. Those involved in the latter incident were between 10 and 20 years old, said Kirsi Kanth of the Helsinki Police.
The amusement park's CEO Risto Räikkönen said that the situation could not be described as a mass fight, but it was developing in that direction and thus park operators decided to close early.
Police suspect ten people of assault and battery, but nobody was detained.
Crowds at Linnanmäki were large on Sunday because of a special two-for-one sale on admission bracelets. The crowd was estimated at between 15,000 and 20,000.